Apple Inoculates OS X Leopard Against Flashback

In the wake of the Flashback malware outbreak that last month infected more than 600,000 Macs, Apple Monday pushed two security fixes for users of OS X 10.5 Leopard.

Flashback was the largest-ever malware outbreak involving OS X users, and at its peak exploited over 600,000 Macs. The malware spread by targeting a Java vulnerability that was first disclosed in a Windows security notice in February 2012. Apple last month released Flashback eradication software for its current Mac operating system, 10.7 Lion, as well as for 10.6 Snow Leopard.

Now, the 10.5 Leopard version of Apple's new Flashback Removal Security Update will likewise search for multiple Flashback variants, including SabPub. "This update removes the most common variants of the Flashback malware," according to the update's release notes. "If the Flashback malware is found, a dialog will notify you that malware was removed. In some cases, the update may need to restart your computer in order to completely remove the Flashback malware."

Apple Monday also released a security update for 10.5 Leopard that disables Java, as well "versions of Adobe Flash Player that do not include the latest security updates, and provides the option to get the current version from Adobe's website," according to the update notes. That mirrors functionality that Apple already introduced for OS 10.7 and 10.6. But to install this update, Leopard users must be running the most recent version--10.5.8--of the operating system.

[ Macs have been safer than Windows PCs, but every security-savvy IT pro knows "safer" isn't "totally safe." Learn why After Flashback, Apple Walled Gardens Won't Help. ]

While 63% of Flashback infections affected OS 10.6 Snow Leopard, and only 11% affected OS 10.7 Lion users, 25% of the infections were traced to OS 10.5 Leopard users, even though it's only used by 13% of all Mac users.

Apple's release of operating system patches to nuke Flashback, as well as its decision to proactively disable unused Java--though it can be reinstalled--and outdated versions of Flash Player have garnered praise from security experts, as well as the developers behind the add-ons.

Notably, Adobe security chief Brad Arkin lauded the update for Safari that automatically disables outdated Flash Player installations. "We welcome today's initiative by Apple to encourage Mac users to stay up-to-date: With the Apple Safari 5.1.7 update released today, Apple is disabling older versions of Flash Player (specifically Flash Player 10.1.102.64 and earlier) and directing users to the Flash Player Download Center, from where they can install the latest, most secure version of Flash Player," he said in a blog post.

Despite the slew of 10.5 fixes, Apple said it is prepping its new OS X 10.8 Mountain Lion operating system for a late summer launch. Mac watchers, however, have seen signs that the operating system might debut during Apple's 2012 Worldwide Developer Conference, which will be held in San Francisco June 11 through June 15.

Some commentators have wondered whether Apple, with the introduction of OS 10.8, would continue its practice of no longer releasing new security patches for all but the current and previous operating system, which in this case would be 10.7 Lion. But Apple's Monday introduction of 10.5 fixes shows that, at least in the case of a mass malware outbreak of Flashback proportions, Apple appears ready to roll out relevant patches, especially since older versions of its operating system would have the potential to keep infecting newer ones.

"It's encouraging to see Apple has not left users of this older version of the Mac OS X operating system completely out in the cold when it comes to protecting against the latest threats," said Graham Cluley, senior technology consultant at free Mac antivirus maker Sophos, in a blog post. "Clearly they realize that it's not good for the Apple Mac's image if older computers connected to the Internet are harboring malware that could cause problems for others in the Mac community."

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